Genotyping of methicillin-resistant Staphylococcus aureus strains from two hospitals in Bangalore, South India

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen in India, and up to 70% methicillin resistance has been reported from hospitals in various parts of India. Hospitals use phenotyping for the most part, and molecular genotyping is not done. Here we report on the genotyping of 82 single-patient isolates from two hospitals in Bangalore, South India, for the first time. Most of the strains possessed type III or IIIA staphylococcal cassette chromosome (SCCmec) cassettes, and we did not detect strains with type I, IA, or II cassettes. Most isolates also contained the type III cassette chromosome recombinase (ccr) AB region. Multilocus sequence typing (MLST) and staphylococcal protein A (spa) typing of a selected number of isolates have been carried out. Although most isolates that were chosen for MLST and spa typing had the same patterns, they were quite diverse in their pulsed-field gel electrophoresis (PFGE) patterns. PFGE, MLST, and spa typing of the Indian strains revealed that they are related to the previously described Hungarian and Brazilian clones.

FIG. 1.

(A) PFGE patterns of SmaI digests of MRSA isolates from the two hospitals. Lanes 1 and 12, NCTC 8325; lanes 2 to 5, SJ isolates; lanes 6 to 11, M isolates. (B) Dendrogram based on the similarities derived from the UPGMA and Dice coefficients, using Quantity One software. The scale at the top represents similarity.

FIG. 2.

(A) PFGE patterns of SmaI digests of MRSA isolates from the two hospitals. Lane 6, NCTC 8325; lane 10, HUSA 304 (Hungarian clone); lane 2, HSJ 216 (Brazilian clone); lanes 4, 5, and 9, SJ isolates; lanes 3, 7, and 8, M isolates; lane 1, lambda molecular weight marker. (B) Dendrogram based on the similarities derived from the UPGMA and Dice coefficients, using Quantity One software. The scale at the top represents similarity.